Process for the manufacture of highbulk blended yarns



Aug. 15, 1967 A. ABDEL-MONIEM GORRAFA 3,335,466

.PROCESS FOR THE MANUFACTURE OF HIGH-BULK BLENDED YARNS Filed April 23, 1965 Y Q AV FIG.1

INVENTOR ADLY ABDEL- MONIEM GORRAFA BY am ATTORNEY United States Patent 3,335,466 PROCESS FOR THE MANUFACTURE OF HIGH- BULK BLENDED YARNS Adly Abdel-Moniem Gorrafa, Wilmington, DeL, assignor to E. I. du Pont de Nemours and Company, Wilmington, DeL, a corporation of Delaware Filed Apr. 23, 1%5, Ser. No. 450,369 filaims. (Cl. 19145.7)

ABSTRACT OF THE DISCLOSURE A process for manufacturing high-bulk blended yarns of 65% to 33% bulk giving staple-length fiber of low yield point and 35% to 67% conventional staple length fiber of higher yield point and higher initial modulus wherein carding is effected with a slower than normal peripheral licker-in speed, greater than normal clearance between the main cylinder and fiber Workers thereof, and drafting effected with roll settings greater than the length of the conventional fiber.

This invention relates to production of high-bulk textile yarns from staple fibers of low yield point, and more specifically to a method for producing high-bulk blendedfiber yarns which impart to fabrics woven therefrom a high degree of covering power.

Of late, certain crimped synthetic textile fibers have been introduced, the crimp of which is either developed as a result of an inherent ability of the fibers to crimp or as a result of an exterior influence such as the mechanical stuffer-box and the air-jet. Some fibers, even more recently introduced, possess the characteristic of spontaneously and irreversibly elongating when immersed in boiling water or exposed to high temperatures, as disclosed by Kitson et al. in US. Patent No. 2,952,879 dated Sept. 20, 1960. Unfortunately, many of these fibers possess relatively low yield-points and, as a result of tensions applied to them in the process of making yarn from staple, the desirable features of these fibers are seriously impaired in the textile products. The effect of conventional processing of these fibers, either in homogeneous or heterogeneous fiber blends, is that the yarn so produced either as-spun or after bulking treatment (e.g., boil-off) has possessed only a low degree of bulkiness instead of the high degree of bulkiness which would be expected by virtue of the desirable properties of the com- .ponents used.

This invention provides a process for producing a high-bulk textile yarn with pleasing aesthetical attributes, of a synthetic staple-length fiber of low yield-point blended with one or more other conventional higher yieldpoint and higher initial modulus synthetic or natural fiber components of staple length. Another provision of the present invention is a process for producing a highbulk textile yarn from a mixture of fibers, one of which possesses an inherent ability to crimp and a low yieldpoint, the other(s) being a conventional high yield-point, high initial-modulus synthetic or natural fiber(s). A further provision is a process for producing a high-bulk textile yarn from a mixture of staple fibers, one of which is of a spontaneously and irreversibly elongatable nature and of low-yield point, and the other(s) a conventional high-initial-modulus, high yield-point synthetic or natural fiber(s).

The present invention is the improvement in the process of blending, carding and drafting a mixture of staplelength fibers for spinning into yarn in a conventional 3,335,466 Patented Aug. 15, 1967 spinning system, of blending (A) 35% to 67% of conventional staple-length fiber, having an irreversible yieldpoint greater than 0.8 gram per denier and an initial modulus greater than 20 grams per denier, with (B) 65% to 33% of bulk-giving fiber having a length about 65% to of the length of fiber (A), an irreversible yield-point less than 0.8 gram per denier and an initial modulus less than 30 grams per denier, and then carding and drafting the blend with certain readily-achieved adjustments in normal processing procedure. The longer fiber (A) has unexpectedly been found to protect such stress sensitive fibers as spontaneously and irreversibly elongatable fibers and'crimped fibers of low irreversible yield-point.

In the drawing, which illustrates forms of apparatus, conventionally used in the cotton system spinning, that are suitable for use in the process of this invention,

FIGURE 1 is a schematic side view of a carding machine, and

FIGURE 2 is a schematic side view of a Saco-Lowell type of drafting and spinning frame.

The apparatus of FIGURE 1 is a conventional cotton card. A lap 1 of mixed fibers is fed to licker-in 3 onto the card cylinder 4 and is carried under flats 5 which Work the fibers. The flats are interconnected to form a continuous belt supported on rollers 6 and drive wheel 7. The carded fibers are transferred from the card cylinder 4 to doifer 8 from which a fiber web is stripped, condensed, and passed through a calender 9 and emerges as sliver 10. The speed of the licker-in is adjustable relative to the speed of the cylinder and the clearance between the flats and the cylinder is adjustable, Certain changes from conventional operating adjustments for these members will be discussed subsequently.

For spinning, the fibers 10, either as a sliver or as a roving, are fed between back draft rolls 12 and 14 of the spinning frame illustrated in FIGURE 2. The fibers are supported on apron 16 which moves about tension pulley 18, bottom back draft roll 14, idler roll 20, and nose bar 22. The fibers then pass between forward draft rolls 24 and 26, through pigtail guide 28 and are wound up with twist on bobbin 30. The distance x between the back and the forward drafting rolls is adjustable; for use in the process of the present invention the roll settings are somewhat greater than the length of the fiber (A) component mentioned previously. The roll settings will also be greater than the length of the fiber (B) component, since this has a staple length of about 65% to 85% of fiber (A).

To facilitate the understanding of the invention, reference is made to the following definitions and explanation of terms, it being understood that these terms, whenever employed herein in the description and claims, are to be construed in accordance with such definitions and explanations.

Staple length is a term applied to the most important fiber length in a technical sense. With cotton, the staple length corresponds very closely to the modal or most frequent length when the fibers are measured in a straightened state. With man-made fibers, the staple length corresponds to the length at which the continuous filament was cut to staple. Therefore, a 1.25-inch (32-mrn.) staple length does not by definition imply that each and every fiber is of 1.25-inch (32-mm.) length.

Crimp is a term applied to fibers which are not straight in their spacial configuration. Such fibers are either helically ordered or consist of segments of definite length, the axis of each segment being spacially different from adjoining segments.

Crimp index is a measure of the degree of crimping and is calculated from the formula:

Crimp Index: 100

where L is the extended fiber length measured under a load of 0.050 gram/denier and I. is the relaxed fiber length measured under a load of 0.002 gram/denier. A decrease in the crimp index will be noted after a fiber has been stressed above the yield point. This becomes more and more serious as the stress is increased.

Yield-point is a measurement of the maximum amount of stress which can be applied to a fiber without causing plastic flow to the extent that a desirable quality of the fiber, such as crimp, or spontaneous and irreversible extensibility, is significantly decreased after removal of the stress. This irreversible yield-point is measured by plotting on the graph the stress applied to the fiber as the ordinate and the resulting strain so induced as the abscissa. The slope of the tangent to the initial nearlystraight portion of this plot is the initial modulus. A line is then drawn tangentially to the second nearly-straight portion of the plot. The point at which this second line intersects the first initial tangent is translated to the ordinate and the corresponding point on the ordinate is the irreversible yield-point in grams per denier.

The term spontaneously and irreversibly elongatable refers to the property whereby a fiber or filament increases permanently in length upon immersion in boiling water or exposure to heat without tension being applied to the ends of the fiber or filament; i.e., the fiber or filament does not retract to its original length when cooled or dried. The numerical value {S.E.) is the percentage boil-off length increase, based on the initial length of the fiber; it is determined by immersing the fiber into water at 100 C. for 5 minutes, drying the fiber at room temperature, and expressing the change in length of the fiber as a percentage of its length prior to immersion in boiling water. Spontaneous and irreversible extensibility of the fiber is expressed as a positive percentage value for boil-off length increase. Spontaneously and irreversibly elongatable fibers will be termed herein as S.E. fibers and staple made therefrom as SE. staple.

Covering power is the degree which a fabric hides a bcakground. Two measurements are applied to quantitatively describe such effect; viz., 1,. and 1,.

I percent is calculated by the formula:

where RC is reflectance of a white plate covered with fabric; RC is reflectance of a black plate covered with fabric; R is reflectance of an uncovered white plate; R is reflectance of an uncovered black plate. Reflectance is measured by using a photoelectric reflection meter Model No. 610 manufactured by Photovolt Corp. of New York. White and black plates used are Photovolt Catalog Nos. 6162 and 6163. A green tri-stimulus filter is used, and the light intensity reflected from the fabric and/ or the plate at a 45 angle from the plane of the plate is measured.

I is a measurement of light transmission through a fabric. A Durst No. 609 Projector manufactured by Durst S.A., Italy, is used as the light source and diffusing element. Light from the projector is cast upon a fabric sample and the amuont of light transmitted through the fabric is measured by a Photo Multiplier Microphotometer, Catalog No. -211, manufactured by American Instrument Co., Inc., Maryland. The reading of the microphotometer with the fabric sample in the apparatus is recorded as percentage points of the original amount of light transmitted with no fabric sample in the apparatus. This measurement of percentage light transmission is referred to hereinafter as 1,.

Relative viscosity pertains to the ratio of the viscosity of a 10% solution of the polymer in a mixture of 10 parts of phenol and 7 parts of 2,4,6-trichlorophenol (by weight) Percent I X 100 to the viscosity of the phenol trichlorophenol mixture, per se, measured in the same units at 25 C.

The present invention is not concerned with mixtures of fibers which yield satisfactory yarn-bulk upon conventional processing to a yarn, but is limited to blends of high and low yield-point fibers for which satisfactory results are not obtained when processed by conventional processing methods. In order to produce high-bulk yarn from such blends by the process of the present invention, a mixture of fibers of different lengths must be employed.

The shorter fiber is the bulk-giving fiber which possesses either a high degree of present crimp, crimp-potential, or the ability to spontaneously and irreversibly elongate upon immersion in boiling water, and is characterized by a yield-point of about 0.4 to 0.8 gram per denier (especially ones of less than 0.7 gram per denier) and an initial modulus of less than 30 grams per denier (especially ones of less than about 25 grams per denier). Among suitable fibers of the above characteristics are inherently crimpable polyesters and copolymers thereof, polyester copolymers which are bulked by methods of the type described in Breen and Lauterbach Ser. No. 287,- 464, now U.S. Patent No. 3,186,155, and those polyesters which are rendered spontaneously elongatable by methods disclosed in Kitson et al. U.S. Patent No. 2,952,879. Preferably, the shorter fiber is a copolymer of polyethylene terephthalate and polyethylene sulfoisophthalate which is bulked as disclosed by Breen and Lauterbach.

The longer fiber exhibits a yield-point greater than 0.8 gram per denier and preferably more than 0.9 gram per denier. The initial modulus of the longer fiber is greater than that of the shorter fiber and must be greater than 20 grams per denier to achieve adequate results. To achieve best results it is greater than 30 grams per denier. Among suitable longer fibers which meet these specifications are synthetic fibers of polyethylene terephthalate polymer or copolymers, polyamides and copolymers thereof, polyacrylonitrile and copolymers of acrylonitrile, rayon and natural fibers such as cotton and Wool.

The differential length of the fibers is essential in the process of this invention. If a mixture of the species of fibers noted above as the short-fiber with the species shown above as the long-fiber, each of the staples being of the same length characteristics, is blended and conventionally spun into a yarn, the yarn will possess an extremely low-bulk quality, or the fabric made therefrom will not develop bulk after finishing. The improved product of the present invention is only obtained by having the stronger, higher-yield-point fiber of longer length than the shorter, lower-initial-modulus, lower-yield-point fiber. In general, the shorter fiber is about -85% (preferably %85%) of the length of the longer fiber. The exact length of each fiber, of course, depends upon the spinning system used, the commercial availability of staple sizes and the particular machine settings most economically practicable to the manufacturer. Thus, if cotton-system machinery is employed to process staple of 1.5-inch (38 mm.) average length, the preferred blend of the present invention is 15-inch (38 mm.) longer staple(s) and about 1.2-inch (30 mm.) shorter staple. The relative amount of shorter staple in the mixture may be from 33% to 65% and is preferably about 45%.

In order to obtain the improved high-bulk yarn, using the staple mixture as herein described, certain mechanical modifications are made in the carding operation. The peripheral speed of the licker-in, for example, must be substantially lowered from the normal speed of about 800 to 1000 ft./min. (405 to 510 cm./sec.) to a speed of 350 to 600 ft./min. (about to 310 cm./sec). The adjustment of the peripheral speed is relative to the yieldpoint and initial modulus characteristics of the shorter fiber. Thus, if the shorter fiber of the mixture possesses a yield-point of about 0.8 gram/ denier, the staple is preferably carded at a licker-in speed of approximately 600 ft./min. (about 310 cm./sec.), while if the yield-point of the shorter fiber is about 0.4 gram per denier, the staple is preferably carded at a peripheral licker-in speed of 330 ft./min. (170 cm./sec.). Moreover, the clearance between the card cylinder and fiber workers, such as the flats or other coacting members, is increased by about to 40% of the conventional setting in order to achieve a yarn of high bulk by the present invention.

The conventional setting is peculiar to each different card. What is meant by a widening of 10% to 40% is that, in the practice of the present invention, it will be beneficial to increase the setting by this proportion over the setting that is practicable for normal staple.

This invention is further illustrated by the following examples of preferred embodiments, although it will be understood that these examples are for purposes of illustration and are not intended to limit the scope of the invention.

Example I This example illustrates the effect of using the method of the present invention to produce a yarn yielding improved fabric cover and aesthetics.

A polyester copolymer of 98 mol percent polyethylene terephthalate and 2 mol percent'polyethylene sulfoisophthalate is melt spun into a yarn. Crimp and bulk are then imparted to the yarn according to the procedures of fluid-jet bulking disclosed in Example XX of Breen and Lauterbach, Ser. No. 287,464. The yield-point of the fiber is 0.50.6 gram per denier and initial modulus is approximately grams per denier. This yarn is divided into two portions; one portion is cut to 1.25-inch (32 mm.) staple and the other portion is cut to 1.5-inch (38 mm.) staple. A polyester homopolymer of the same composition is melt spun to yarn of yield-point of 0.9 to 1.0 gram per denier and initial modulus approximately 35 grams per denier. This yarn is cut to 1.5-inch (38 mm.) staple. Four staple blends are prepared; the first is composed of 33% of the 1.25-inch portion of the former staple and 67% of the latter staple; the second is composed of 33% of the 1.5-inch portion of the former staple and 67% of the latter staple; the third is composed of 50% of the 1.25-inch portion of the former staple and 50% of the latter staple; the fourth is composed of 50% of the 1.50-inch portion of the former staple and 50% of the latter staple. These staples are blended at the picker and subsequently carded according to the conventional cotton spinning system with the exception that, in the carding operation, the peripheral speed of the licker-in is adjusted to 330 feet per minute (about 170 cm. per second) and the clearance between the card cylinder and the flats is widened by 30% of the normal setting used with the particular card. The above blends are each spun to 30/1 cc. (19.7 TeX) and Woven in a Warp of 30 denier, semidull, normal tenacity, continuous filament polyethylene terephthalate homopolymer. The loom construction is 96 x 78 (38 ends per cm. x 31 picks per cm.). The finished fabric properties are as shown in Table I.

Example 11 This example illustrates that, although the machinery modification described above contributes to the improved yarns of this invention, different length staple in accordance with the above-mentioned rules is essential for best results.

A polyester copolymer of 98 mol percent polyethylene terephthalate and 2 mol percent polyethylene sulfoisophthalate is melt-spun into a yarn. Crimp and bulk are then imparted to the yarn according to the procedure of fluid-jet bulkingdisclosed in Breen and Lauterbach Ser. No. 287,464, Example XX. The yield-point of this yarn is 0.48 to 0.53 gram per denier and the initial modulus is about 15 to grams per denier. The yarn is then cut to 1.25-inch (32 mm.) staple. A standard semidull polyethylene terephthalate homopolymer yarn is prepared.

The yield-point of this yarn is approximately 1.0 gram per denier, the initial modulus is about 35 grams per denier and the RV is 15.5. This yarn is then cut into 1.5- inch (38 mm.) staple. A staple mixture is then prepared consisting of 33% of the shorter staple, 34% of the longer staple and 33% domestic cotton by blending slivers of each component at the draw frame. The blend is then spun into a yarn according to the conventional cotton spinning system with the exception that in carding the polyester components, the peripheral speed of the licker-in is adjusted to 350 ft./min. (180 cm./sec.) and the clearance between the card cylinder and the flats is 30% wider than the normal clearance used with the particular card.

A control yarn is then prepared using the same species fibers and percentages as described above with the exception that the bulked staple is cut to 1.5-inch (38 mm.) length. The licker-in speed and the clearance between the card cylinder and the flats are identical to those condi tions used in preparing the test yarn of this example.

The test yarn is spun to 50/1 cc. (11.8 Tex) and woven into a fabric of x 72 (47 ends per cm. x 28 picks per cm.) loom construction. The bulk of this fabric after normal finishing is 3.73 cc./gm. and the grab-strength in the filling direction is 25.4 lbs. (11.5 kg.) at 32% elongation.

The control yarn is spun and woven in the same manner into an identical fabric construction. This fabric after normal finishing possesses a bulk of 3.13 cc./gm. and a grab-strength in the filling direction of 25.1 lbs. (11.4 kg.) at 33% elongation.

Bulk and grab-strength are measured in accordance with ASTM procedure D1777-60T at 5 gm./crn. pressure and ASTM procedure D-1682-59 Method G-E, respectively.

Example III This example illustrates the preservation of the spontaneously and irreversibly elongatable quality of fibers by using the method of the present invention in contrast to the prior art method which negates this desirable characeristic of the fiber.

A polyester copolymer consisting of 98 mol percent polyethylene terephthalate and 2 mol percent polyethylene sulfoisophthalate is spun to a yarn and rendered spontaneously and irreversibly elongatable according to the process disclosed by Kitson et al. in US. Patent No. 2,952,- 879 dated Sept. 20, 1960. The yield-point of this yarn is 0.65 gram per denier. The initial modulus is 17.3 grams per denier and spontaneous elongation is 8.5%. The yarn is then cut to 1.25-inch (32 mm.) staple. A polyester copolymer consisting of 98 mol percent polyethylene terephthalate and 2 mol percent polyethylene sulfoisophthalate is prepared and spun to a yarn of yield-point 0.9 to 1.0 gram per denier and initial modulus approximately 35 grams per denier. This yarn is cut to 1.5-inch (38 mm.) staple. A staple blend consisting of 33% of the shorter S.E. staple, 34% of the longer staple and 33% domestic cotton [1.1251.250-inch (29-32 mm.) staple] is then prepared by blending slivers of each component at the draw frame, the slivers being prepared by picking and carding each component separately. The staples are then spun into a yarn according to the conventional cotton spinning system with the exception that in carding the shorter staple, the peripheral speed of the licker-in is adjusted to 350 ft./min. (about cm./sec.), and the clearance between the card cylinder and the flats is widened by 40% of the normal setting used in the operation of the particular card. After two passages of drawing, spontaneously and irreversibly elongatable fiber is separated from the sliver and found to have a spontaneous elongation of 4.02%.

A control yarn is then prepared by the above procedure with the following exceptions: The S.E. fiber is cut to 1.5-inch staple; the staple mixture consists of 65% of this staple and 35% domestic cotton [1.l251.250-inch 7 (29 to 32 mm.) staple]. The conventional cotton system is used without the modifications described above. After 8 (38 ends per cm. x 31 picks per cm.). Table I shows the properties of these fabrics.

TABLE I Fabric Filling Blend Filling Finished Weight Air It Count, cc. Construction Perm.

337 1.25 inch (32 mm.) bulked staple Example I Experlmental g Eg g lg g g f mp1 30 1 100 x 85 2. 45 126 3. 7

1.50 inc 8 mm. u e s ap e Example I Conn {egg1.5ineh czgmm.) ll l e nt staple 30/1 X 85 50 13B 4 5 1.25 inc 2 mm. u re s ap c Example I Experimental g 8 g Eg g g g g f staple /1 100 x 2. 45 126 3. a

r 50 1.5 inc 8mm. u e sape Example I contol {50 7? 1.50 inch (38 mm.) lligh-yield-point staple-- 30/1 100 x 85 45 144 7 35% 1.125 inch (28.6 mm.) SE. staple Example IVExperimental 30% Domestic Cotton 30/1 100 x 85 2.50 8 1 2. 78

35% 1.5 inch (33 mm.) high-yield-point staple 35% 1.5 lnch (38 mm.) S.E. staple Example IV-Control 30% Domestic Cotton 30/1 100 x 84 2. 45 114 4. 42

35% 1.5 inch (38 mm.) high-yield-point staple 35% 1.125 inch (28.6 mm.) 8.11. staple. Example IV-Expenrnental 30% Domestic Cotton 50/1 100 x 85 1.60 285 11.2

35% 1.5 inch (38 mm.) high- 35% 1.50 inch (38 mm.) S.E. staple. Example IVCont-rol 30% Domestic Cotton 50/1 100 x 85 1. 60 307 13.1

35% 1.5 inch (38 mm.) high-yield-point staple 1 Percent light transmission measurement previously defined. Air permeability is measured in accordance with ASTM D-737-46.

two processes of drawing, spontaneously and irreversibly elongatable fiber separated from the sliver possesses a spontaneous elongation of -0.88%, i.e., it actually shrinks upon immersion into boiling water instead of extending.

Example IV This example illustrates the efiect of the method of the present invention on fabrics woven from ternary-blend staple yarn.

A polyester copolymer consisting of 98 mol percent polyethylene terephthalate and 2 mol percent polyethylene sulfosiophthalate is spun to a yarn and rendered spontaneously and irreversibly elongatable according to the process disclosed by Kitson et al. in US. Patent No. 2,952,879. The yield-point of this yarn is approximately 0.65 gram per denier, and the initial modulus is approximately 17 grams per denier. This yarn is divided into two portions; one portion is cut to 1.5-inch (38 mm.) staple and the other is cut to 1.125-inch (28.6 mm.) staple. A polyester copolyrner of the same composition is melt-spun to a yarn but not rendered spontaneously and irreversibly elongatable. The yield point of this yarn is approximately 0.9 to 1.0 gram per denier and the initial modulus is approximately 35 grams per denier. This yarn is cut to 1.5-inch (38 mm.) staple. Two staple blends are prepared: One blend consists of 50% of 1.125-inch (28.6 mm.) 5.13. fiber and 50% of the 1.5-inch (38 mm.) high-yield-point staple and the other blend consists of 50% of 1.5-inch (38 mm.) SE. fiber and 50% of 1.5-inch high-yield-point staple. Each blend is picked and carded according to the conventional cotton spinning system with the exception of licker-in speed adjustment and clearance adjustment as indicated in Example I. Slivers of domestic cotton [1% Example V This example further illustrates the improved bulk and cover of the fabrics prepared from yarns spun according to the present invention.

A polyester homopolymer of polyethylene terephthalate is melt spun into a yarn of 27.5 R.V. A helical crimp is imparted to the yarn according to the jet-quenching procedures disclosed in Kilian US. Patent No. 3,050,821, dated Aug. 28, 1962. The initial modulus of this yarn is below 20 grams per denier and the yield-point is below 0.8 gram per denier. This yarn is divided into two portions: The first portion is cut to l-inch (25.4 mm.) staple and the second portion is cut to 1.5-inch 38 mm.) staple. A standard, semidull, polyethylene terephthalate homopolymer yarn is prepared. The initial modulus of this yarn is 35 grams per denier and the yield-point is 0.9 to 1.0 gram per denier. This yarn is cut into staple of 1.5-inch (38 mm.) length. Two staple blends are then prepared, the first blend consisting of 50% of l-inch helicallycrimped fiber and 50% of 1.5-inch high-initial-modulus staple, and the second blend consisting of 50 of 1.5-inch helically-crimped staple and 50% 1.5-inch high-initialmodulus staple. Slivers of domestic cotton of approximately 1.125-inch staple length (29 mm.) are blended with each of the above blends at the drawing step and each blend is subsequently spun into yarns of 50/1 cc. (11.8 Tex) of the final composition as shown in Table II. Fabrics are woven from each yarn, at 100 x 72 (39 ends per cm. x 28 picks per cm.) loom construction and finished at 106 x 78 (42 ends per cm. x 31 picks per cm.) construction. Table II shows the properties of these fabrics.

TABLE 11 Fabric Warp and Filling Yarn Weight Specific Air I Bulk Perm.

33% 1.0 inch (25.4 mm.) helically crimped staple Example V-Expcrimcntal 38% 1.5 inch (38 mm.) high-yield-points taple 2.6 3.3 5.0

34% Domestic cotton 33% 1.5 inch (38 mm.) helically crimped staple Example V-C0ntrol 33% 1.5 inch (38 mm.) high-yield-point Stap1e.- 2. 6 2.8 6. 6

34% Domestic cotton inch staple (29 mm.)] are blended at the draw frames with the above blends of this example and each blend is subsequently spun into 30/1 cc. (19.7 Tex) and 50/1 cc. (11.8 Tex) yarns of the final composition shown in Table I. The yarns are woven in a warp of 30-denier semidull, normal tenacity continuous filament polyethylene tereph- Example VI This example illustrates the effect of using the method of the present invention to produce high cover textile fabrics in contrast to the method of the prior art.

A polyester copolymer of 98 mol percent polyethylene terephthalate and 2 mol percent polyethylene sulfoisothalate homopolymer at a loom construction of 96 x 78 75 phthalate is melt spun into a yarn. Crimp and bulk are 9 then imparted to the yarn according to the procedures of fluid-jet bulking disclosed in Example XX of Breen and Lauterbach, Ser. No. 287,464. The yarn is then cut to 1.25- inch (32 mm.) staple. The yield-point of the fiber of this yarn is 0.5 to 0.6 gram per denier, and the initial modulus E covering-power and have a pleasing hand and other aesthetical qualities.

Since many diiferent embodiments of the invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited is approximately grams per denier. A standard, semiby the specific illustrations except to the extent defined dull polyethylene terephthalate homopolymer fiber is in the following claims. prepared and melt-spun. The relative viscosity of this fiber I claim: is 15.5, the yield-point is approximately 1.0 gram per 1. In the process of blending, carding and drafting a denier and the initial modulus is approximately 35 grams 1O mixture of staple-length fibers for spinning into yarn in per denier. This continuous filament product is then cut a conventional spinning system, the improvement for ininto staple of 1.5-inch (38 mm.) length. A staple mixcorporating bulk-giving fibers of low yield-point to proture is then prepared consisting of 50% of the shorter vide high bulk in the yarn product which comprises, staple and 50% of the longer staple. After carding, slivers blending of domestic cotton [1.125-1250 inch (29 to 32 mm.) 15 (A) 35% to 67% of conventional staple-length fiber staple] are blended with the above mixture at the draw having an irreversible yield-point greater than 0.8 fi'arne to yield a blend composition of 33% shorter polygram per denier and an initial modulus greater than ester, 33% longer polyester and 34% cotton. The blend grams per denier with is then spun into 30/1 cc. (19.7 Tex) and 50/1 cc. (11.8 (B) 65% to 33% of bulk-giving fiber having a length Tex) yarns according to the conventional cotton spinning 20 about 65% to 85% of the length of fiber (A), an system with the exception that at the carding of the polyirreversible yield-point less than 0.8 gram per denier ester components the peripheral speed of the licker-in is and an initial modulus less than 30 grams per denier, adjusted to 330 ft./min. (170 cm./ sec.) and the clearance (C) ardin the blend with the peripheral speed f th between the card cylinder and the fiats is set at approxilicker-in within the range of about 350 to 600 ft./ mately 28% wider than the normal setting. min., the speed being relative to the yield point and A control yarn is prepared consisting of the following initial modulus characteristics of the bulk-giving blend staple: 65 of the highinitial-modulus polyester fiber, with clearance between the card cylinder and yarn mentioned above in the present example, cut to 1.5- the fiber workers of about 10% to 40% greater than inch (38-mm.) staple and 35% domestic cotton of the the normal clearance thereof, and same variety as mentioned above in this example. This (D) drafting with roll settings greater than the length staple blend is divided into two portions; the first portion of fiber (A). is spun to a yarn of 30/1 cc. (19.7 Tex) and the second 2. The process as defined in claim 1 wherein the bulkportion is spun to yarn of 50/1 cc. (11.8 Tex). In pregiving fiber (B) is crimped polyethylene terephthalate paring the control yarns normal card settings and speeds fiber having a yield-point of about 0.4 to 0.7 gram per are used. denier and an initial modulus less than 25 grams per Four woven fabrics are prepared from the test yarns, denier. and four woven fabrics are prepared from the control 3. The process as defined in claim 1 wherein the bulkyarns. The fabrics are then finished by conventional progiving fiber (B) is spontaneously elongatable polyethylcedures. Table III shows the construction of these fabrics ene terephthalate fiber having a yield-point of about 0.4 and compares the improved properties of the product of 40 to 0.7 gram per denier and an initial modulus less than the present invention to the product of the prior art con- 25 grams per denier. trol fabric, 4. The process as defined in claim 1 wherein the con- TABLE III Fabric Cc. Warp/Fill Loom Const. Fin. Constr. Wgt. Thickness Air I Permeability /1 50/1 120 x 72 135 x 80 3. 25 12. 0 40.1 73.1 1. 54 50/1 50/1 120 x 72 131 x 80 3. 10 12.1 64. 4 72.9 2. 52 50/1 30/1 120 x 72 135 x 77 3.96 14. 0 20. 5 80.7 1. 22 50/1 30/1 120 x 72 131 x 80 3. 95 13. 7 30.1 76. s 1. 50/1 50/1 120 x 60 135 x 67 2.89 12.0 58.8 76. 5 1. 86 50/1 50/1 120 x 60 131 X 2.88 11.7 103. 0 71. 2 3. 29 50/1 30/1 120 x 60 135 x 3. 72 14. 0 33. 7 80.0 1.40 50/1 30/1 120 x 60 131 x 66 3. 41 13. 3 55. 2 74. 7 2.13

Air Permeability is measured in accordance with ASTM D-737-46. Weight" is measured in accordance with ASTM D-l910 Section 27.

It has been demonstrated that techniques previously used to manufcature spun y-arn from staple are inadequate to protect and enhance desirable attributes of the new spontaneously and irreversibly elongatable fibers and certain new crimp fibers as hereinabove described which, although possessing desirable features, lose them by processing methods of the known art to such extent that the yarns spun therefrom bear little semblance to the original fiber. The process of the present invention enables the manufacture of useful yarns from these sensitive fibers, the bulk of which has heretofore been unknown in using these fibers even after considerable expenditure of valuable resources. Fabrics may be woven or knitted from these yarns to be used for garments and other purposes. The fabrics so produced possess a considerable degree of References Cited UNITED STATES PATENTS 2,985,940 6/1961 Weldon 2872 3,007,227 11/1961 Moler 57-140 FOREIGN PATENTS 870,017 6/1961 Great Britain.

ROBERT R. MACKEY, Primary Examiner. 

1. IN THE PROCESS OF BLENDING, CARDING AND DRAFTING A MIXTURE OF STAPLE-LENGTH FIBERS FOR SPINNING INTO YARN IN A CONVENTIONAL SPINNING SYSTEM, THE IMPROVEMENT FOR INCOPPORATING BULK-GIVING FIBERS OF LOW YIELD-POINT TO PROVIDE HIGH BULK IN THE YARN PRODUCT WHICH COMPRISES, BLENDING (A) 35% TO 67% OF CONVENTIONAL STAPLE-LENGTH FIBER HAVING AN IRREVERSIBLE YIELD-POINT GREATER THAN 0.8 GRAM PER DENIER AND AN INITIAL MODULUS GREATER THAN 20 GRAMS PER DENIER WITH (B) 65% TO 33% OF BULK-GIVING FIBER HAVING A LENGTH ABOUT 65% TO 85% OF THE LENGTH OF FIBER (A), AN IRREVERSIBLE YIELD-POINT LESS THAN 0.8 GRAM PER DENIER AND AN INITIAL MODULUS LESS THAN 30 GRAMS PER DENIER, (C) CARDING THE BLEND WITH THE PERIPHERAL SPEED OF THE LICKER-IN WITHIN THE RANGE OF ABOUT 350 TO 600 FT./ MIN., THE SPEED BEING RELATIVE TO THE YIELD POINT AND INITIAL MODULUS CHARACTERISTICS OF THE BULK-GIVING FIBER, WITH CLEARANCE BETWEEN THE CARD CYLINDER AND THE FIBER WORKERS OF ABOUT 10% TO 40% GREATER THAN THE NORMAL CLEARANCE THEREOF, AND (D) DRAFTING WITH ROLL SETTINGS GREATER THAN THE LENGTH OF FIBER (A). 